kyynärluusta

The kyynärluusta, known in English as the ulna, is one of the two long bones in the forearm. It is located on the medial side of the forearm, meaning it runs along the side of the little finger. The ulna is longer than the radius, the other bone in the forearm, and articulates with the humerus at the elbow joint, forming the hinge of the elbow. At the wrist, the ulna articulates with the carpal bones, though this articulation is indirect and often involves the triangular fibrocartilage complex. The proximal end of the ulna features the olecranon, which forms the bony prominence of the elbow, and the trochlear notch, which grasps the trochlea of the humerus. The distal end of the ulna has a head and a styloid process. The ulna plays a crucial role in forearm rotation, although the radius is more involved in supination and pronation. It provides attachment points for numerous muscles of the forearm and hand, contributing to their function. Fractures of the ulna can occur in various locations, including the shaft, olecranon, or distal end, and are often caused by direct trauma or falls.